Micro Pump Systems

ABSTRACT

Discloses is a micro-pump that includes a pump body having a compartmentalized pump chamber, with plural inlet and outlet ports and a plurality of membranes disposed in the pump chamber to provide compartments. The membranes are anchored between opposing walls of the pump body and carry electrodes disposed on opposing surfaces of the membranes and walls of the pump body. Also discloses are applications of the micro-pump including as a heat remover and a self-contained continuous positive airway pressure breathing device.

This application claims priority under 35 U.S.C. §119 to U.S.Provisional Patent Application Ser. No. 61/945,973, filed Feb. 28, 2014,and entitled “Micro Pump Systems”, the entire contents of which arehereby incorporated by reference.

BACKGROUND

This specification relates to pump systems.

Mechanical pump systems and compressor systems are well-known. Pump areused to move fluid (such as liquids or gases or slurries by mechanicalaction. Pumps can be classified according to the method used to move thefluid, e.g., a direct lift pump, a displacement pump, and a gravitypump.

Recently was announced a low-profile high pressure air pump operatingwith piezoelectric technology, by Murata Manufacturing, model MZB1001,micro-blower, a miniature piezoelectric air pump. According to Murata,the pump uses a piezoelectric diaphragm, which vibrates up and down whena sine wave voltage is applied, the vibrations force air into themicro-blower and out through a nozzle on the top of the device.

A somewhat common medical disorder sleep apnea involves a reduction orpause in breathing (airflow) during sleep. Sleep apnea is common amongadults and rare among children. Treatments for sleep apnea can includesurgical procedures or nonsurgical treatments that can involvebehavioral changes dental appliances and mouthpieces. One nonsurgicaltreatment involves CPAP (continuous positive airway pressure) devices.

Continuous positive airway pressure (CPAP) is a non-surgical treatmentthat uses a machine to supply air pressure to hold a user's airway openso that it does not collapse during sleep. A machine delivers airthrough a nasal or face-mask under pressure. The machine blows heated,humidified air through a tube to a mask that is worn snugly to preventthe leakage of air. Masks come in several forms including nasal pillows,nasal masks, and full-face masks. The CPAP machine is a little largerthan a toaster. It is portable and can be taken on trips. However,existing CPAP treatments are not easy to use, as it is not easy to sleepwith a mask that blows air into the nose.

SUMMARY

According to an aspect, a micro-pump includes a pump body, the pump bodyhaving a pump chamber that is compartmentalized into pluralcompartments, with the pump chamber having a first plurality of inletports providing fluid ingress into the pump chamber and a secondplurality of outlet ports providing fluid egress from the pump chamber,a third plurality of membranes disposed in the pump chamber, with thethird plurality of membranes anchored between opposing walls of the pumpbody and providing the plural compartments with the pump chamber, and afourth plurality of electrodes, with a first pair of the fourthplurality of electrodes disposed on a second different pair of opposingwalls of the pump body, and a remaining ones of the fourth plurality ofelectrodes disposed on major surfaces of the membranes.

The follow are some embodiments within the scope of this aspect.

Inlets and outlets are on the same wall of the pump body. The firstplurality of inlets and the second plurality of outlets are on the samewall of the pump body, and the first plurality of inlets have a firstset of connections to a source and the second plurality of outlets havea second, different set of connections to a sink and with the secondplurality of outlets isolated from the first set of connections. Theinlets and the outlets are on opposing walls of the pump body. Themicro-pump includes a fifth plurality of valves, a first portion ofwhich are disposed adjacent the first plurality of inlets and a secondportion of the valves disposed adjacent the second plurality of outlets.The fifth plurality of valves are flap valves. The micro-pump isconfigured to be driven by a set of electrical signals applied to thefourth plurality of electrodes to cause the third plurality of membranesdisposed in the pump chamber to deflect according to polarities ofvoltages applied to the fourth plurality of electrodes. The set ofelectrical signals cause a first one of the plural compartments tocompress and cause at least one adjacent one of the plural compartmentsto expand substantially simultaneously. The micro-pump includes a drivecircuit to produce waveforms to apply to the electrodes.

According to an additional aspect, a micro-pump includes first andsecond micro-pump modules having a pump body, a membrane havingelectrically conductive electrodes on major surfaces thereof, and a pumpend that form a pump compartment, each of the first and secondmicro-pump modules having at least an inlet port providing fluid ingressinto the pump compartment and an outlet port providing fluid egress fromthe pump compartment, at least a third micro-pump module having a pumpbody and a membrane having electrically conductive electrodes on majorsurfaces thereof, with the third micro-pump module sandwiched betweenthe first and second micro-pump modules.

The follow are some embodiments within the scope of this aspect.

The inlet and the outlet of each module are on a same wall of the pumpbody. The first plurality of inlets and the second plurality of outletsare on the same wall of the pump body, and the first plurality of inletshave a first set of connections to a source and the second plurality ofoutlets have a second, different set of connections to a sink and withthe second plurality of outlets isolated from the first set ofconnections. The inlet and the outlet of each module are on opposingwalls of the pump body. The micro-pump includes a plurality of valvesdisposed adjacent inlets and outlets. The valves are flap valves havinga beam member and a stop.

According to an additional aspect, a cooling device for an electricalcomponent, include a micro-pump having a pump body forming a pumpchamber having a plurality of compartments, with the pump chamber havinga first plurality of inlet ports providing fluid ingress intocompartments of the pump chamber and a second plurality of outlet portsproviding fluid egress from compartments of the pump chamber and a thirdplurality of membranes disposed in the pump chamber, with the thirdplurality of membranes anchored between opposing walls of the pump body,and a fourth plurality of electrodes, with a first pair of the fourthplurality of electrodes disposed on a second different pair of opposingwalls of the pump body, and a remaining portion of the fourth pluralityof electrodes disposed on a surface of each of the membranes, a heatplate having a first surface configured to attach to the electricalcomponent and a second surface that is in thermal communication with themicro-pump.

The follow are some embodiments within the scope of this aspect.

The micro-pump is connected to the heat plate. End ones of thecompartments have a corresponding wall of the pump body and one of thethird plurality of membranes providing the end compartments and withintermediate ones of the compartments having a pair of membranesproviding the intermediate compartments.

According to an additional aspect, an airway pressure breathing deviceincludes a ring body having air passages through the ring body,terminating in a pair of end portions, with each end portion having atleast one outlet in a first surface of the end portion, and a micro pumpsupported by the ring body, the micro pump configured to pump ambientair through the air passages in the ring body to the end portions.

The follow are some embodiments within the scope of this aspect.

The airway pressure breathing device includes a battery to provide apower source for the micro pump, the battery supported on the pump body.

One or more of the above aspects may provide one or more of thefollowing advantages.

Micro pumps can be made using micro fabrication methods and can be usedfor performing micro pumping processes that are widely implemented inindustrial, medical, and biological applications. The micro pumps cantransport the fluids at high flow rates. The micro pumps can be used asreasonably inexpensive and possibly disposable apparatus for variousapplications, including to dose medications, can be used in artificialorgans. The micro pumps can be used as vacuum pumps based on their highcompression capabilities and can be used in heat transfer applicationssuch as in fuel cell systems, replacing traditional air compressors tomove air to provide oxygen for fuel cell reactions and remove reactionbyproducts including water vapor and waste heat. Compared to thetraditional air compressors, which can be expensive, loud, big, heavy,consumes high power, and easy to wear out, the micro pumps are low cost,quiet, small, e.g., in the millimeter scale, light weight, e.g., in thescale of milligram to gram, and generally will consume relatively lowpower in comparison to conventional pumps. Moreover, the micro pumps aremechanically robust.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention are apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIGS. 1A and 1B are functional block diagrams of a micro pump operatingin two opposite phases of a pumping cycle.

FIG. 1C illustrates the micro pump of FIGS. 1A, 1B with membranes in anominal uncharged position.

FIG. 1D illustrates the micro pump of FIGS. 1A, 1B with flap valves anddrive circuitry.

FIG. 2A is an assembled view of a stack of assembled module layers.

FIG. 2B is an exploded view of module layers.

FIG. 2C is an assembled view of the module layer of FIG. 2B.

FIG. 2D is an exploded view of an intermediate module layer.

FIGS. 3 and 4 are plots of voltage waveforms for application toelectrodes of a micro pump.

FIG. 5 is a block diagram of an exemplary drive circuit.

FIG. 6 is a block diagram of micro pumps arranged in an exemplary gridconfiguration.

FIG. 7 is a perspective view of micro pumps integrated in a die frame.

FIGS. 8A and 8B are respective top side view and bottom side view of anexemplary cooling device in a cooling arrangement.

FIGS. 9A and 9B are respective perspective view and front view of anairway pressure breathing device.

FIG. 9C is a perspective view of an alternative airway pressurebreathing device.

FIG. 10 is a block diagram of a CPAP (continuous positive airwaypressure) breathing device.

FIGS. 10A-10F are views of an exhalation valve.

FIGS. 11A and 11B show details of exemplary sliding “T” and “omega”valves.

FIGS. 11C and 11D are blowup views showing details of the exemplarysliding “T” valve and “omega” valve, respectively.

DETAILED DESCRIPTION Overview

Micro pumps can be made using micro fabrication methods and can be usedfor performing micro pumping processes that are widely implemented inindustrial, medical, and biological applications. For example, micropumps can be incorporated in lab-on-a-chip systems, fuel cells, highflux electronic cooling systems, and biochemistry systems. The micropumps can transport fluids, e.g., gas or liquids, in small, accuratelymeasured quantities. In some implementations, the micro pumps cantransport the fluids at high flow rates, e.g., about microliters persecond to about a few milliliters per second, and/or high pressure,e.g., about thousandths of one psi to about tenths of one psi. The micropumps can be designed such that the fluid transport, the flow rates,and/or the pressure are scalable.

In medical applications, the micro pumps can be used as reasonablyinexpensive and possibly disposable means of chemical dosing. Forexample, the micro pumps can be implanted in a human body to dosemedications, e.g., into blood streams, and treat chronic diseases. Themicro pumps can also be used in artificial organs.

The micro pumps can be used as vacuum pumps based on their highcompression capabilities. The micro pumps when used as vacuum pumps,i.e., micro vacuum pumps can be used in miniature systems for chemicaland biological analyses. For example, the micro vacuum pumps can be usedto produce and maintain a vacuum in an ionization chamber of a massspectrometer, so that ions produced in the ionization chamber exit thechamber without colliding with air molecules.

In fuel cell systems, the micro pumps can be used as air pumps,replacing traditional air compressors, to move air in the systems toprovide oxygen for fuel cell reactions and remove reaction byproductsincluding water vapor and waste heat. Compared to the traditional aircompressors, which can be expensive, loud, big, heavy, consumes highpower, and easy to wear out, the micro pumps are low cost, quiet, small,e.g., in the millimeter scale, light weight, e.g., in the scale ofmilligram to gram, and generally will consume relatively low power incomparison to conventional pumps. Moreover, the micro pumps aremechanically robust.

In one example implementation, micro fuel cells are formed to include asmall, light-weight and highly distributed air subsystem. The airsubsystem incorporates micro pumps with three dimensional (3D) protonexchange membrane (PEM) structures on silicon wafers. Fabricated on themicron scale, the micro fuel cell architecture simplifies the airmovement requirements for fuel cell reactions and for removing reactionby products. Compared to traditional fuel cells, fuel cells formed onsilicon wafers can achieve improvement in power per volume productionand weight per volume by an order of magnitude.

Micro Pump Systems Micro Pumps

Referring to FIG. 1 a micro pump 100 is shown to include a singlecompartmentalized pump chamber 104. The pump body 102 includes two walls110, 112 along the pumping direction 114, and two fixed end walls 106,108 opposite to each other along a direction perpendicular to thepumping direction 114. The walls 106, 108, 110 and 112 define the singlechamber 104 that is compartmentalized by membranes. That is, between thetwo end walls 106, 108, membranes 116, 118, 120, 122, 124, 126 extendfrom the wall 110 to the wall 112, separating the pump chamber 104 intoseven compartments 130, 132, 134, 136, 138, 140, 142. In thisimplementation, each compartment includes an inlet and an outlet definedin the walls 110, 112, respectively. For example, the compartment 130includes an inlet 150 in the wall 110 and an outlet 152 in the wall 112.Other inlets and outlets are not labeled.

The compartments 130-142 are fluidically sealed from each other. In someimplementations, different compartments can have the same inlet and/orthe same outlet (not shown in the figure) and these differentcompartments may fluidically communicate with each other. Twocompartments 130, 142 at the opposite ends of the pump chamber 104 havewalls provided by a fixed wall of the pump body 102 and a membrane.Intermediate compartments between the compartments 130, 142 have wallsprovided by two membranes with the micro pump 100 having at least oneand generally many intermediate compartments, each of which intermediatecompartment walls are provided by two membranes. The micro pump 100 canpump fluids, e.g., gas or liquid, with selection of materials takinginto consideration the type of fluid that the pump will be configured topump.

Although six membranes are shown in the figures, the pump chamber can beextended with additional intermediate compartments, as each compartmentcan be viewed as formed of a module layer (see, FIGS. 2A-2D), and thepump 100 is formed of a stack of the module layers, as described furtherbelow.

Electrodes (not explicitly shown in FIGS. 1A and 1B, see, FIGS. 2A and2C) is attached to each of the membranes 116-126 and optionally to theend walls caps 106, 108. The electrodes (not explicitly shown) areconnected to a drive circuit (see FIGS. 3-5) that delivers voltages tothe electrodes to activate the membranes through electrostaticattraction/repulsion. When the electrodes have no voltage the membranesare not active and the membranes rest at nominal positions. Eachmembrane at rest can be substantially parallel to the end walls 106, 108and the compartments 132-140 can have the same nominal volume V_(i).When activated, the electrodes receive a voltage potential as shown inFIG. 1A and FIG. 1B. FIG. 1A and FIG. 1B show the same chamber but withdifferent phases of signals applied to the electrodes, as discussedbelow. For clarity the reference nos. in FIG. 1A, in general, are notrepeated for FIG. 1B.

In some embodiments, the distance between two adjacent membranes intheir nominal positions is about 50 microns and the nominal volume V canrange from nanoliters to microliters to milliliters, e.g., 0.1microliters. In some implementations, the compartments 130, 142 each hasa nominal volume V_(e) that is half the nominal volume of theintermediate compartments 132-140. For example, the distance between themembrane 116 in its nominal position and the end wall 106 or between themembrane 126 in its nominal position and the end wall 108 is about 25microns. The nominal volume V_(e) can range from nanoliters tomicroliters to milliliters, e.g., 0.05 microliters. The compartments130-142 can also have different sizes. The sizes can be chosen based on,e.g., manufacturing, power consumption, and application considerations.For example, the compartments 130, 142 having a width of 25 microns canallow a start-up function with a reduced peak drive voltage. Drivevoltages are discussed further below. As an example, the micro pump 100can have an internal volume having a length of about 1.5 mm, a width ofabout 1.5 mm, a total height (the cumulative height of differentcompartments) of 0.05 mm, and a total volume of about 0.1125 mm³.

Compared to a conventional mechanical pump used for similar purposes,the micro pump 100 uses less material, and thus is subject to lessstress, and is driven using less power. The micro pump 100 has a size inthe micron to millimeter scale, and can provide wide ranges of flowrates and pressure. Approximately, a potential flow rate that could beprovided by micro pump 100 can be calculated as the total volume of themicro pump 100 times the drive frequency.

Generally, the flow rate can be in the scale of nanoliters tomicroliters to milliliters. Generally, the pressure is affected by howmuch energy, e.g., the drive voltage, is put into the micro pump 100. Insome implementations, the higher the voltage, the larger the voltage,and the upper limit on voltage is defined by break down limits of themicro pump 100 and the lower limit on the voltage is defined by themembrane's ability to actuate. The pressure across a micro pump 100 canbe in the range of about a micro psi to tenths of a psi. A selectedrange of flow rate and pressure can be accomplished by selection of pumpmaterials, pump design, and pump manufacturing techniques.

The described micro pump 100 is a displacement type pump in thereciprocating category. Pumping occurs in two alternating operations ofa fluid charging cycle and a fluid discharging cycle through theactuation of a pump chamber of the micro pump. In the chargingoperation, the pump chamber is opened to a lower pressure source and thefluid fills into the chamber. In the discharging operation, the fluidinside the pump chamber is compressed out of the pump chamber to ahigher pressure sink.

Generally, while a conventional pump chamber is compressed when a singlemembrane moves towards a fixed wall of the chamber, the pump chamberdiscussed above in conjunction with FIGS. 1A, 1B comprises multiplemembranes each anchored between two fixed walls. The fixed walls arepump body layers that form multiple compartments separated by pairs ofadjacent membranes. The first and last ones of the compartments areformed by a membrane and a fixed wall that is part of an end cap of thebody, but intermediate compartments are provided by pairs of adjacentmembranes.

Comparing FIGS. 1A and 1B, which shows two operational states of thesame micro pump 100. In a first half pump cycle a first set ofcompartments are compressed and a second set of compartments areexpanded.

For instance in FIG. 1A, end compartments 130 and 142 are showncompressed as are intermediate compartments 134 and 138 in the firsthalf pump cycle. The compression occurs in the end compartments 130 and142 when membranes 116 and 126 move towards walls 106 and 108 and forcompartments 134 and 138 when adjacent membranes 118, 120 and 122, 124move towards each other. The movement of these membranes reduces thevolume of the respective end compartments 130 and 142 and intermediatecompartments 134 and 138 to discharge fluid (gas or liquid) from thecompartments. Simultaneous to the compression of those compartments,adjacent compartments 132, 136 and 140 (all here being intermediatecompartments) are charged when respective sets of membranes 116, 118;120, 122; and 124, 126 move away from each other to expand therespective chamber volumes.

As shown in FIG. 1B, in a second half pump cycle, end compartments 130and 142 are shown expanded as are intermediate compartments 134 and 138.The expansion occurs in the end compartments 130 and 142 when membranes116 and 126 move away from walls 106 and 108 and for compartments 134and 138 when adjacent membranes 118, 120 and 122, 124 move away fromeach other. The movement of these membranes increases the volume of therespective end compartments 130 and 142 and intermediate compartments134 and 138 to charge fluid (gas or liquid) into those compartments.Simultaneous to the expansion of those compartments, adjacentcompartments 132, 136 and 140 (all here being intermediate compartments)are discharged when respective sets of membranes 116, 118; 120, 122; and124, 126 move towards each other to reduce the respective chambervolumes.

That is, when actuated, each membrane of a pump chamber can move in twoopposite directions about a central, nominal location at which themembrane rests when it is not actuated.

In operation, the membrane of the conventional pump chamber forms asingle pump chamber compartment, which is used in pumping. Fluid, e.g.,gas is charged and discharged once during the charging and dischargingoperations of a pumping cycle, respectively. The gas outflows onlyduring half of the cycle, and the gas inflows during the other half ofthe cycle.

In the instant micro pump 100, each compartment 130, 132, 134, 136, 138,140, and 142 is used in pumping. Thus, as shown in FIG. 1A in a firsthalf of a pump cycle fluid is pumped out of chambers 130, 134, 138, and142, while gas enters chambers 132, 136, and 140 simultaneously. Asshown in FIG. 1B, in the second half of a pump cycle the operation isreversed, with fluid pumped out of chambers 132, 136, and 140 while gasenters chambers 130, 134, 138, and 142, simultaneously.

Various implementations are possible. For example, two membranes betweentwo fixed end walls form three compartments for pumping. The micro pump100 can have a higher efficiency and can consume less energy than aconventional pump performing the same amount pumping, e.g., because theindividual membranes travel less distance and therefore are driven less.The efficiency and energy saving can further increase with more than asingle compartment between the two fixed end walls compartments. Thus, amicro-pump 100 can have from one to several to 100's or moreintermediate chambers. Here in FIGS. 1A and 1B, five (5) intermediatechambers are shown.

Generally, to perform pumping, each compartment includes a gas inlet 150and a gas outlet 152. The inlets and the outlets include valve, e.g.,passive valves that open or close in response to pressure applied to thevalves. In some implementations, the valves are flap valves that aredriven by a differential pressure across the valves produced by flows ofgas into or out of the pump compartments. Because no active driving isrequired, the flap valves can reduce the complication of pump operation.

In other implementations, the valves are sliding valves that are drivenby differential pressure across the valves produced by flows of gas intoor out of the pump compartments, and which may be more desirable givenenergy considerations involved with flexing the flap valve. Exemplarysliding valves are discussed in FIG. 11.

Alternatively, it is also possible to build micro pump 100 in avalve-less configuration using nozzles and diffusers.

FIG. 1C shows membranes of the micro pump 100 in their central, nominalposition.

Referring now to FIG. 1D, the membranes (not numbered but the same as inFIG. 1A) are driven to move by an electrostatic force. An electrode(generally 162) is attached to each of the major surfaces of each of thefixed end walls and membranes. During the charging operation of acompartment, adjacent electrodes of a compartment have the same positiveor negative voltage applies and thus would tend to cause the twoelectrodes and therefore the two membranes to repel each other. Duringthe discharging operation of a compartment, two adjacent electrodes ofthe compartment have the opposite positive or negative voltages, causingthe two electrodes and therefore, the two membranes to attract to eachother. The two electrodes of a compartment form a parallel plateelectrostatic actuator. The electrodes generally have small sizes andlow static power consumption. A high voltage can be applied to eachelectrode to actuate the compartment. But the actuation can be performedat a relatively low current.

As described previously, each membrane of the micro pump 100 moves intwo opposite directions relative to its central, nominal position(illustrated for micro pump 100 in FIG. 1C). Accordingly, compared to acompartment in a conventional pump, to expand or reduce a compartment bythe same amount of volume, the membrane of this specification travels adistance less than, e.g., half of, the membrane in the conventionalpump. As a result, the membrane experiences less flexing and lessstress, leading to longer life and allowing for greater choice ofmaterials. In addition, because the travel distance of the membrane isrelatively small, the starting drive voltage for the electrode on themembrane can be relatively low. Accordingly, less power is consumed. Fora compartment having two membranes, since both membranes are moving, thetime it takes to reach the pull-in voltage can be shorter.

Still referring to FIG. 1D, in some implementations, a drive circuit 166for applying voltages to the electrodes takes a low DC voltage supplyand converts it to an AC waveform. The frequency and shape of thewaveform can be controlled by a voltage controlled oscillator. The drivevoltage can be stepped up by a multiplier circuit to the required level.Flap valves 164 are also shown and are driven by differential pressureacross the valves 164 produced by flows of gas into or out of the pumpcompartments.

Micro pumps 100 having the above described features can be manufacturedusing various methods such as MEMS processing techniques so-called rollto roll (R2R) processing. The materials for a micro pump 100 are chosenbased on the features to be provided by the micro pump 100 and themethod of manufacturing the micro pump. Below are some criteria forchoosing the materials of the different parts of the micro pump.

Pump body and valves—The material used for the body of a pump may bedefined by the requirements of the flap valves 164. Flap valves can bemade of the same material as the body. In some implementations, thematerial needs to be strong or stiff enough to hold its shape to producethe pump chamber volume, yet elastic enough to allow the flap valves tomove as desired. In addition, the choice can be influenced by thegeometric design of the flap valves. In some implementations, thematerial is etchable or photo sensitive so that its features can bedefined and machined/developed. Sometimes it is also desirable that thematerial interact well, e.g., adheres, with the other materials in themicro pump. Furthermore, the material is electrically non-conductive.Examples of suitable materials include SU8 (negative epoxy resist), andPMMA (Polymethyl methacrylate) resist.

Membrane—The material for this part forms a tympanic structure that isused to charge and discharge the pump chamber. As such, the material isrequired to bend or stretch back and forth over a desired distance andhas elastic characteristics. In some implementations, the membranematerial is impermeable to fluids, including gas and liquids, iselectrically non-conductive, and possesses a high breakdown voltage.Examples of suitable materials include silicon nitride, and Teflon.

Electrodes—This material is electrically conductive. Because theelectrodes do not conduct much current, the material can have a highelectrical resistance, although the high resistance feature is notnecessarily desirable. The electrodes are subject to bending andstretching with the membranes, and therefore, it is desirable that thematerial is supple to handle the bending and stretching without fatigueand failure. In addition, the electrode material and the membranematerial adhere well, e.g., do not delaminate from each other, under theconditions of operation. Examples of suitable materials include verythin layers of gold and platinum.

Electrical interconnects—The drive voltage is conducted to the electrodeon each membrane of each compartment. Electrically conducting paths tothese electrodes can be built using conductive materials, e.g., gold andplatinum.

Other materials—when MEMS processing is used in manufacturing the micropump, a sacrificial filling material, e.g., polyvinyl alcohol (PVA), canbe used. The sacrificial filling material may also be used in R2Rprocessing. In some implementations, solvents are used in themanufacturing process, which may place additional requirements on thevarious building materials of the micro pump. It may be possible toprint some of the electrical circuit components into the membranes.Sometimes a release material can be used for creating valve movement.

In general while certain materials have been specified above, othermaterials having similar properties to those mentioned could be used.

In FIGS. 2A-2D, a modularized micro pump is shown.

Referring to FIG. 2A a modularized micro pump 200 is comprised of modulelayers 201 (FIGS. 2B and 2C) to form end compartments 200 a, 200 b ofthe pump 200. The modularized micro pump 200 is also comprised of manymodule layers 250 (FIG. 2D) to form intermediate compartments 200 c ofthe pump 200.

The valves in the micro pump 200 can be replaced by single valvesconnected to the input and the output or the individual valves in eachlayer can be staggered.

Referring now to FIG. 2B, the module layers 201 each include a pump endcap 202 forming a fixed pump wall (similar to walls 106, 108 FIGS. 1A,1B). An electrode 208 is attached to the pump end cap 202 for activatinga compartment 209.

A single module layer 201 forms a portion of a pump body 204 between thepump end cap 202 with the electrode 208, and a membrane 206 along withan electrode 210 that is attached to the membrane 206 on the oppositeside of the pump body 204 (similar as the membrane 116, 126 in FIGS. 1A,1B). The electrode 210 includes a lead 212 to be connected to a drivecircuit external to the module layer 200.

The membrane 206, the pump end cap 202, and the pump body 204 can havethe same dimensions, and the electrodes 208, 210 can have smallerdimensions than the membrane 206 or the other elements. In someimplementations, the membrane 206 has a dimension of about microns bymicrons to about millimeters by millimeters, and a thickness of about 5microns. The pump body 204 has an outer dimension of about microns bymicrons to about millimeters by millimeters, a thickness of about 50microns, and an inner dimension of about microns by microns to aboutmillimeters by millimeters. The thickness of the pump body defines thenominal size of the compartment 209 (similar to compartments 130, 142FIG. 1A). The electrodes 210, 202 have dimensions that substantiallycorrespond to inner dimensions of the pump body 204. In someimplementations, the electrodes have a surface area of about 2.25 mm²and a thickness of about 0.5 microns. An assembled module layer 201 isshown in FIG. 2C.

Referring now also to FIG. 2C, the pump body 204 includes two passivevalves 214, 216, forming an inlet and an outlet, respectively. The inletvalve 214 includes a stopper 218 and a flap 220. The stopper isconnected to the pump body 204 and is located external to thecompartment 130, 140 formed by the pump body. The flap 220 has one end222 attached to the pump body 204 and another end 224 movable relativeto the stopper 218 and the pump body 204. In particular, the end 224 ofthe flap can bend towards the interior of the compartment 130, 140 whena pressure differential is established such that the pressure externalto the module layer is larger than the pressure inside the module layer.For example, such a pressure differential is established during acharging operation in which a fluid flows from outside the module layerinto the compartment 209. When the internal pressure is higher than theexternal pressure, e.g., during a discharge operation in which a fluidflows from the compartment 209 away to the outside of the module layer,the flap 224 bends towards the stopper and is stopped by the stopper218. Accordingly, during the discharge operation, the fluid in thecompartment 209 does not flow out from the inlet valve 214.

The outlet valve 216 also includes a stopper 230 and a flap 232 similarto the stopper 218 and the flap 220, respectively. However, the stopper230 is located in front of the flap 232 along a direction in which thefluid flows into or out of the compartment 209. When the internalpressure is higher than the external pressure, the flap bends away fromthe stopper to open the valve and when the internal pressure is lowerthan the external pressure, the flap bends towards from the stopper toclose the valve. Effectively, during the charging operation, the outletvalve 216 is closed so that the fluid does not flow out of the valve216, and during the discharging operation, the outlet valve 216 is openand the fluid flows out from the valve 216.

Referring to FIG. 2D, intermediate compartments (similar to compartments132-140 FIGS. 1A-B) can each be formed using a module layer 250. Themodule layer 250 includes a pump body 252, an electrode 256, and amembrane 254 formed between the electrode 256 and the pump body 252. Thepump body 252 can have similar or the same features as the pump body204, the electrode 256 can have similar or the same features as theelectrode 208, and the membrane 254 can have similar or the samefeatures as the membrane 206. The module layer 250 also includes flapvalves (not referenced but shown in the figure.)

As described previously, the valves of each pump body can be formedintegrally with the pump body. Although the electrodes are shown as apre-prepared sheet to be attached to the other elements, the electrodescan be formed directly onto those elements, e.g., by printing. Thedifferent elements of the module layers 200, 250 can be bonded to eachother using an adhesive. In some implementations, a solvent can be usedto partially melt the different elements and adhere them together.

Referring back to FIG. 2A, thus multiple, e.g., two, three, or anydesired number of, module layers 250 of FIG. 2D are stacked on top ofeach other to form multiple intermediate compartments in a pump chamber.In the stack 200, each membrane is separated by a pump body and eachpump body is separated by a membrane. To form a complete pump, a modulelayer 201 of FIG. 2B is placed on each of the top and bottom ends of thestack 200 so that the pump end caps of the module layer 201 form twofixed end walls of the pump chamber.

Referring again to FIGS. 1A and 1B, during each pumping cycle, thecompartments are activated such that each compartment charges duringhalf of the cycle and discharges during the other half of the cycle.Adjacent compartments operate in 180 degree phase difference, i.e., whenthe compartment 130 is charging, its adjacent compartment 132 isdischarging, and vice versa. As a result, every other compartmentoperates in phase. In FIGS. 1A and 1B, the compartments are labeled byodd-numbered (“O”) compartments and even-numbered (“E”) compartments,the O compartments are in phase with each other, the E compartments arein phase with each other, and the O compartments are out of phaserelative to the E compartments.

To operate compartments of the pump in their discharging state, voltagesof opposite signs are applied to the electrodes on opposing walls ofthese compartments. For example, as shown in FIG. 1A, the voltage of theelectrode on the fixed wall 106 is negative while the voltage of theelectrode on the membrane 116 is positive, or the voltage of theelectrode on the membrane 118 is positive while the voltage of theelectrode on the membrane 120 is negative, etc. Simultaneously, theother compartments of the pump are operated in their charging state.Voltages of the same signs are applied to the electrodes on opposingwalls of these other compartments. The voltages of opposite signs causethe two opposing walls of the compartments to attract each other and thevoltages of the same signs cause the two opposing walls of thecompartments to repel each other. The fixed walls 106, 108 do not move.However, the membranes 116-126 move towards a direction of theattraction force or a direction of the repelling force. As a result, inhalf of a pumping cycle, the compartments 130, 134, 138, 142 dischargeand the other compartments simultaneously charge (FIG. 1A), and in theother half of the pumping cycle, the compartments 132, 136, 140discharge and the other compartments simultaneously charge (FIG. 1B).

In some implementations, the material of the membranes and the voltagesto be applied to the membranes and the end walls 106, 108 are chosensuch that when activated, each membrane expands substantially half thedistance d between the nominal positions of adjacent membranes. In theend compartments 130, 142 where the distance between the nominalposition of the membrane and the fixed wall is d/2, the activatedmembrane reduces the volume of the compartment to close to zero (in adischarging operation) and expands the volume of the compartment toclose to 2* V_(e). For the intermediate compartments, by moving eachmembrane by d/2, a volume of a compartment is expanded to close to2*V_(i) in a charging operation and reduced to close to zero in adischarging operation. The micro pump 100 can operate at a highefficiency.

The period of the pumping cycle can be determined based on the frequencyof the drive voltage signals. In some implementations, the frequency ofthe drive voltage signal is about Hz to about KHz, e.g., about 2 KHz. Aflow rate or pressure generated by the pumping of the micro pump 100 canbe affected by the volume of each compartment, the amount ofdisplacement the membranes make upon activation, and the pumping cycleperiod. Various flow rates, including high flow rates, e.g., in theorder of ml/s, and pressure, including high pressure, e.g., in the orderof tenths of one psi, can be achieved by selecting the differentparameters, e.g., the magnitude of the drive voltage. As an example, amicro pump can include a total of 15 module layers, including two layers200 of FIG. 2B and 13 layers 250 of FIG. 2C. This example micro pump canbe drive at a frequency of about 843 Hz and consumes power of about 0.62mW, and provides a flow rate of about 1.56 ml/s at about 0.0652 psi.

In some implementations, four types of electrical signals are used todrive the membranes. The four types are:

-   -   V−: a DC reference for all the voltages; may be used to drive        some membranes directly;    -   V+: a DC high voltage used to drive some membranes directly and        switched for others;    -   V1: a periodic AC waveform used to drive some membranes to        control operation. It includes a 50% duty cycle and swings        between V− and V+ in one full pumping cycle.    -   V2: identical to V1 except it is 180 degrees out of phase.

Furthermore, based on the phenomenon of pull-in and drop-out voltages,the drive voltage can be reduced to a lower voltage once the highestmagnitude of V1 or V2 has been reached. In particular:

-   -   V1.5: the pull-in voltage value.    -   V2.5: the drop-out voltage value.

Referring now to FIG. 3, six example sets of waveforms 301-306 forapplication onto six electrodes on the fixed wall 106 and the membranes116-124, respectively are shown. The waveforms applied to otheradditional membranes and fixed wall in the micro pump 100 or other micropumps can be derived by the pattern shown in FIG. 3. During pumpingcycles, V− of the first set of waveform 301 is constantly applied to theelectrode on the fixed wall 106. The second set of waveform 302 forapplying to the membrane 116 is in the form of V1. The third set ofwaveform 303 is V+ and is constantly applied to the membrane 118. Thefourth set of waveform 304 is V2 for applying to the membrane 120. Thefifth set of waveform 305 and sixth set of waveform 306 are a repeat ofthe first and second waveforms 301, 302. If additional waveforms areneeded for other membranes, e.g., membranes 124 and 126 (FIG. 1A) therepetition continues with the third and fourth waveforms, and etc.

In some implementations, the magnitudes of V1, V2, V−, and V+ are thesame. In other implementations, magnitudes of at least some of thesevoltages are different. Although a particular pattern of waveforms areshown, the electrodes of the pump 100 can also be activated by otherpatterns of waveforms.

Referring now to FIG. 4, six sets of waveforms 321-326 corresponding tothe six sets of waveforms 301-306 of FIG. 3, respectively are shown. Thedifference between the sets shown in FIG. 4 and the sets shown in FIG. 3is that the AC voltage waveforms V1 and V2 of FIG. 3 are reshaped intoV1.5 and V2.5, respectively to take the advantage of pull-in anddrop-out phenomena.

In this example, in the waveform sets 322, 324, 326, the positive goingvoltage is stepped down (shown by arrows ↓) to a lower voltage once thepull-in point has been reached. This lower voltage is still greater thanthe drop-out voltage so that the membranes remain in their driven state.The next voltage transition defines the beginning of the oppositeoperation, during which a similar voltage level shift is applied. Thenegative going voltage is stepped up (shown by arrows ↑) to a voltagehaving a smaller magnitude. The power consumption of the pump 100 can bereduced by reducing the magnitude of the drive voltages during theirhold time.

Drive Circuitry

Referring now to FIG. 5, an example of drive circuitry 500 for applyingvoltages, such as those shown in FIG. 3 or FIG. 4 is shown. The drivecircuitry 500 receives a supply voltage 502, a capacitance voltagecurrent 504 signal, and pump control 516, and outputs drive voltages 506to electrodes of a micro pump, such as the micro pump of FIGS. 1A and1B. In some implementations, the supply voltage 502 is provided from asystem in which the micro pump 100 is used. The supply voltage can alsobe provided by an isolation circuit (not shown).

The drive circuitry 500 includes a high voltage multiplier circuit 508,a voltage controlled oscillator (“VCO”) 510, a waveform generatorcircuit 512, and a feedback and control circuit 514. The high voltagemultiplier circuit 508 multiplies the supply voltage 502 up to a desiredhigh voltage value, e.g., about 100V to 700V, nominally, 500 V. Othervoltages depending on material characteristics, such as dielectricconstants, thicknesses, mechanical modulus characteristics, electrodespacing, etc. can be used. In some implementations, the high voltagemultiplier circuit 508 includes a voltage step-up circuit (not shown).The voltage controlled oscillator 510 produces a drive frequency for themicro pumps. The oscillator 510 is voltage controlled and the frequencycan be changed by an external pump control signal 516 so that the pump100 pushes more or less fluid based on flow rate requirements. Thewaveform generator circuit 512 generates the drive voltages for theelectrodes. As described previously, some of the drive voltages are ACvoltages with a specific phase relationship to each other. The waveformgenerator circuit 512 controls these phases as well as the shape of thewaveforms. The feedback and control circuit 514 receives signals thatprovide measures of capacitance, voltage and or current in the micropump and the circuit 514 can produce a feedback signal to provideadditional control of the waveform generator 512 of the circuit 500 tohelp adjust the drive voltages for desired performance.

Integration of the Systems in Devices

The micro pump systems described above can be integrated in differentproducts or devices to perform different functions. For example, themicro pump systems can replace a fan or a blower in a device, e.g., acomputer or a refrigerator, as air movers to move air. Compared to theconventional fans or blowers, the micro pumps may be able to performbetter at a lower cost with a higher reliability. In someimplementations, these air movers are directly built into a host at afundamental level in a massively parallel configuration.

In some implementations, the micro pump systems receive power from ahost product into which the systems are integrated. The power can bereceived in the form of a single, relatively low voltage, e.g., as lowas 5V or lower, to a drive circuitry of the micro pump systems, e.g.,the drive circuitry 500 of FIG. 5.

System Configuration

The module layer stack of FIGS. 1A, 1B, and 2D can be viewed as modulelayers connected in parallel. The volume of each individual modulelayer, V_(i) or V_(e), is small. In some implementations, even the totalvolume of all layers in the stack is relatively small. In someimplementations, multiple stacks or micro pumps can be connected inparallel to increase the total volume flow rate.

Similarly, the pressure capability of an individual micro pump isrelatively low. Even though there are multiple module layers in a stack,the layers do not increase the total pressure of the stack because theyare connected in parallel. However, the pressure of the stack can beincreased when multiple stacks or micro pumps are connected in series.In some implementations, the pumps connected in series are driven atdifferent speeds to compensate for different mass flow rates. Forexample, built-in plenums or plumbing in a tree type configuration canalso be used to compensate for different mass flow rates.

Referring now to FIG. 6, rows 610-616 and columns 610′-616′ and column617′of module layer stacks (which can also be called micro pump stacks)610 a-610 e, 612 a-612 e, 614 a-614 e, and 616 a-616 e are shownconnected in a grid configuration 600. The module layer stacks in eachrow 610, 612, 614, 616 are connected in series. The rows 610-616 ofmodule layer stacks 610 a-610 e, 612 a-612 e, 614 a-614 e, and 616 a-616e are connected in parallel via a common input 620 and a common output622.

Effectively, the serially connected stacks in each row can provide atotal pressure substantially equal the sum of the individual stackpressures. In the example shown in the figure, if each stack has apressure of 0.1 psi and each row includes five stacks, then a totalpressure of 0.5 psi is effected by each row, and which is also the totalpressure of the grid 600. The grid 600 has a total flow rate that isfour times the flow rate of each row of stacks.

In the example shown in the figure, each row of stack has a flow rate of1 volume flow (vF). The grid includes four parallel-connected rows,leading to a total flow rate of 4 vF. To achieve a desired pressure anda desired flow rate, a grid similar to the grid 600 can be constructedby choosing the number of stacks to be serially connected and the numberof rows to be connected in parallel.

Alternatively, another series configuration has a common plenum disposedbetween each stage of a grouping of parallel pumps. This configurationwould tend to equalize discharge pressures and thus input pressure atthe next stage. In some implementations, the stacks are relatively smalland many of them can be fabricated in a small area. The plumbing andwiring of the grid can be done at the time of fabrication of theindividual stacks and can be done in a cost effective manner.

Example Applications

As described above, air can be used for an electrochemical reaction andcooling, e.g., in fuel cells. Generally, the amount of air used forcooling is many times more than for the reaction.

Referring to FIG. 7, a fuel cell with an integrated micro pump system700 with fluid inputs 700 a and outputs 700 b is shown. The micro pumpsystem 600 (or 100 or 200) having features described above areintegrated directly into a die frame 702 that contains fuel cells 704.When multiple dies frames are used, generally, there is a minimumspacing among the dies and some of this space can be used to house themicro pump systems 600 with no additional volumetric overhead to thedies. An exemplary fuel cell is disclosed in U.S. application Ser. No.10/985,736, filed Nov. 9, 2004, now U.S. Pat. No. 7,029,779, andentitled “Fuel cell and power chip technology,” the contents of whichare incorporated herein by reference in their entirety.

Integrating the air pump systems can effectively divided the air movingfunction into many, e.g., thousands of parts, minimizing the need forblowers or fans to move the air. The micro pumps can be massmanufactural at a low cost, have small sizes and light weight, bereasonably powerful and consumes low power, allowing for the massivedistribution of air movement. The micro pump systems 600 can be used anytime air (or liquid) needs to be moved in a tight space.

Another such application is the cooling of electronic components likethe CPU.

Referring now to FIGS. 8A and 8B, the micro pump (100, 200, 600) is usedto cool circuits/devices, (e.g., central processor units, etc.) that runat very high temperatures, as well as, e.g., solar cells and LEDlighting.

As an example, FIGS. 8A and 8B show the top side view and bottom sideview of a CPU cooler 800. Instead of a large heat sink and fanarrangement, one or more layers of micro pumps 802 point directly at acooling plate 804, for an impingement effect, that is affixed to theCPU. In some implementations, the CPU cooler 800 can remove 150 watts ofheat. The cooler has a low profile and can be used in computer designsthat have little available space.

The micro pump systems can be used to pump a liquid through a coolingplate fastened to the CPU to remove and transfer heat, by the liquid, toa distant location. For example, the hot liquid carrying the heat can bepumped through a radiator and additional micro pumps can be used to blowair to cool the radiator.

The micro pump systems can also blow air across a heat sink used in atraditional approach; or can be built into the heat sink. As describedpreviously, the micro pump systems can be configured to provide anincreased pressure to push air further. The micro pump systems can alsobe distributed throughout a host device without needing air ducts.

Referring now to FIGS. 9A and 9B, an autonomous device for treatingbreathing disorders 900 (device) is shown. The device 900 is a CPAP type(continuous positive airway pressure) breathing device. However, thedevice 900, unlike CPAP machines, is an autonomous device that is localto the nose and which provides a required amount of air flow at arequired pressure to treat various breathing disorders such asobstructive sleep apnea (“OSA”).

The CPAP breathing device 900 is shown in the form of a nose ring. Otherarrangements are possible (see FIG. 9D). The device 900 has passages 902for air inlets and micro pumps 600 (FIG. 6) disposed in the body 904 ofthe device 900, as shown. The device may also contain valves (See FIGS.10 AND 10A-10F) to provide for exhalation. The ends 904 a, 904 b of thedevice 900, which fit into the nose of a user, provide airflow viapassages 905 a, 905 b, and sealing and are connected via a ring portion903 within which can be disposed a power source, e.g., battery (notshown).

As the micro pump systems are small and can move a significant amount ofair, the micro pump system is built into the device 900, e.g., toprovide relief to many people who have sleep apnea or obstructivebreathing disorder (OBD). The device 900 can be a self-contained devicethat has a small size (e.g., fitting under the nose) and a light weight(e.g., as light as a few grams), and can be operated using batteries.

In some implementations, the device 900 can include exhalation valves(discussed below) whereas in other implementations the exhalation valvesmay be omitted.

In some implementations, the device 900 can be rechargeable, e.g., thebatteries can be recharged. In others the device can be disposable. Auser can wear the device at night and throw it away each day.Alternative arrangements are possible such as the use of air-metalbatteries in the devices. The air-metal batteries, (e.g., air-zinc) areactivated and last for a period of time, and which thereafter aredisposed of.

Device 900 is configured to fit into a user's nose and suppliespressurized air flow from the micro pump 600 (or 100, 200) built intothe ring. The device 900 thus does not require hoses or wires to anotherdevice (e.g., a machine) and the device uses a self-contained powersource, e.g., a battery that is configured to operate for about afull-night's sleep, e.g., about eight hours or so. The device 900 doesnot need straps. The device can be configured to stop blowing air into auser's nose when a user is exhaling or when a user is in a pause statejust prior to inhaling. The device 900 has an exhalation valve thateliminates exhalation resistance (fighting against oncoming air orcutting off the end of exhalation prematurely).

The device 900 can sense pressure to turn on and off the micro airpumps. The device 900 senses pressure on every breath and at differentpoints in the breathing cycle to configure operation of the micro airpumps to close the exhalation valve at the “end” of the exhalationcycle. This device responds to the user on a breath by breath basis.

The device 900 is small, light-weight and fits under a use's nose,making a seal in the user's nose to hold the device in place. The devicecan provide proper pressure for apnea treatment during a pause periodand proper hypopnea pressure range during an inhalation period. Thedevice 900 can be disposable, thus would not require cleaning, can below cost. Moreover, due to its relative comfort compared to existingCPAP machines, the device 900 promotes compliance as the device iscomfortable, require no straps, masks or tethers.

Referring now to FIG. 9C, a conceptual view of an alternativeconfiguration for a CPAP device 960 is shown. In this configuration, theCPAP device 960 includes a body 962 that houses a micro pumps 600 herehaving 57 component-pump elements denoted as 966, and an exhalationvalve (see FIGS. 10A-10F). The CPAP device 960 has cushioned plugs 964a, 964 b with air passages through the plugs that provide a nasalinterface. The cushioned plugs are made of a generally rubbery materialthat make a tight fit when inserted into a user's nostrils. The CPAPdevice 960 has one or as shown two outlets 968 a, 968 b for exhilarationof air.

Referring now to FIG. 10, a schematic, e.g., of the configurations shownin FIGS. 9A-9C, an exhalation valve 980 coupled to a micro pump 600within the CPAP device 900 or 960 (pumps 966). The exhalation valve 980is coupled between the micro pumps 600 (100 or 200 as well) and inlets964 a, 964 b and outlets 968 a, 968 b of the device 900, as shown. Theexhalation valve 980 is of a butterfly configuration and uses air flowfrom the micro pumps to close the valves 980 at the end of anexhalation/beginning of pause in breathing and at the beginning ofexhalation, the exhalation valve 980 opens even as the micro pumps blowsair on the exhalation valves 980.

The device 900 is configured to select how much of the micro pumps' 600air flow is needed to push the valve 980 shut. Pressure from the micropumps 600 will hold the exhalation valve 980 shut prior to exhilaration.All of the exhalation air flow from the user is applied to theexhalation valve 980 to open the exhalation valves 980. The shape ofvalves' flaps may be optimized to assist the exhalation valve 980 tostay open during exhalation. In addition, weak magnetics may also beused to keep exhalation valve 980 open or closed depending on details ofa design. The exhalation air from a user would generally be sufficientto overcome a minimum amount of air flow from the micro pump to keep theexhalation valves 980 closed.

Referring now to FIGS. 10A-10F, various views of a conceptual exhalationvalve 980 are shown. FIGS. 10A-10F show a butterfly valve configurationthat is used for the exhalation valve 980. Valve 980 is illustrated andincludes a body 981, an inlet 982, ports 984 a and 984 b (984 b shownonly in the view of FIG. 10F), outlet ports 985 and a valve flap 986.The flap valve 986 is rotatable about an axial member 988 to open andclose a passageway between the ports 984 a, 984 b and outlet port 985,denoted by the large arrow 989. The micro pump 600 applies air throughinlet 982 to close the flap valve 986. In the context of FIG. 10 andFIG. 9C, the inlet 982 is coupled to an output of the micro pump, theports 984 a, 984 b are coupled to the plugs 964 a, 964 b (with airpassages) and the outlet is coupled to one or both of the outlets 968 a,968 b.

Referring now to FIGS. 11A and 11B details of exemplary a sliding valve1010 (a “T valve”) used on output ports and a sliding valve 1020 (an“omega valve”) used on input ports to the chambers e.g., 209 of themicro pump, e.g., 200 (FIG. 2B).

Recalling that the chamber 209 is produced from the pump body 204 andmembranes 206 (FIG. 2B) (or end walls of the pump body). In FIG. 11A, aportion of the material 1000 that is used to produce the pump body 204provides the T valve 1010 at what would be an output port of a micropump chamber. The T valve 1010 includes a flat member 1012 that providesa valve to close off the output port and with the flat member 1012connected to a stem member 1014 that resides in a compartment 1017formed from regions 1018. Outlets from the chamber are provided byregions 1016.

In FIG. 11A, another portion of the material 1000 that is used toproduce the pump body 204 provide the omega valve 1020 at what would bean input port of a micro pump chamber. The omega valve 1020 includes apiston, like member 1022 that provides a stop for the omega shapedmember 1024 that is somewhat semi-circular with horizontal arms 1024 athat provides a valve to close off the input port and with the omegashaped member 1024 having vertical arms 1024 b. The omega shaped memberis confined to the region (not referenced) form between the pistonmember 1022 and the omega member 1024 by the piston like member 1022.Inlets from the chamber are provided by regions 1026.

Referring now to FIG. 11B the etched body 1000′ has the sliding valve1010 (“T valve”) on output ports and the sliding valve 1020 (“omegavalve”) on input ports and which are formed by removing excess materialfrom the material of the body guided by the etch lines 1002, as shown,leaving each of the sliding valves 1010 and 1020 to move freely withinvery confined regions, according to pressure applied to the chamber butnot being free to move outside of the confined regions. The T valve 1010has the flat member 1012 close off the output port, and is confined inthe region defined by 1016 and 1017, whereas the mega valve 1020 isconfined by the region 1026 and region 1027.

FIGS. 11C and 11D show the sliding valve 1010 (“T valve”) on outputports and the sliding valve 1020 (“omega valve”) on input ports at ahigher magnification.

In some implementations, the micro pump systems can also be used tosense distance between membranes by measuring capacitance between themembranes. The micro pumps include electrodes, each pair of whichforming an electrostatic actuator, which is effectively a variablecapacitor having two conductive plates, i.e., the electrodes, spacedapart at some distance. When a voltage is applied across the twoelectrodes, the electrodes move towards or away from each other. As thedistance between the electrodes changes, so does the capacitance. Thecapacitance increases as the electrodes move closer and decreases as theelectrodes move apart. Accordingly, the capacitance between a pair ofelectrodes can provide information about the distance between the pair.

In some implementations, the information can be applied to determining anumber of parameters of the system. For example, quantities includingpressure, volume, flow rate, and density can be measured.

Elements of different implementations described herein may be combinedto form other embodiments not specifically set forth above. Elements maybe left out of the structures described herein without adverselyaffecting their operation. Furthermore, various separate elements may becombined into one or more individual elements to perform the functionsdescribed herein. Other embodiments are within the scope of thefollowing claims.

1. A micro-pump comprising: a pump body, the pump body having a pump chamber that is compartmentalized into plural compartments, with the pump chamber having a first plurality of inlet ports providing fluid ingress into the pump chamber and a second plurality of outlet ports providing fluid egress from the pump chamber; a third plurality of membranes disposed in the pump chamber, with the third plurality of membranes anchored between opposing walls of the pump body and providing the plural compartments with the pump chamber; and a fourth plurality of electrodes, with a first pair of the fourth plurality of electrodes disposed on a second different pair of opposing walls of the pump body, and a remaining ones of the fourth plurality of electrodes disposed on major surfaces of the membranes.
 2. The micro-pump of claim 1 wherein inlets and outlets are on the same wall of the pump body.
 3. The micro-pump of claim 1 wherein the first plurality of inlets and the second plurality of outlets are on the same wall of the pump body, and the first plurality of inlets have a first set of connections to a source and the second plurality of outlets have a second, different set of connections to a sink and with the second plurality of outlets isolated from the first set of connections.
 4. The micro-pump of claim 1 wherein the inlets and the outlets are on opposing walls of the pump body.
 5. The micro-pump of claim 1 further comprising a fifth plurality of valves, a first portion of which are disposed adjacent the first plurality of inlets and a second portion of the valves disposed adjacent the second plurality of outlets.
 6. The micro-pump of claim 1 wherein the fifth plurality of valves are flap valves or sliding valves.
 7. The micro-pump of claim 1 wherein the micro-pump is configured to be driven by a set of electrical signals applied to the fourth plurality of electrodes to cause the third plurality of membranes disposed in the pump chamber to deflect according to polarities of voltages applied to the fourth plurality of electrodes.
 8. The micro-pump of claim 1 wherein the set of electrical signals cause a first one of the plural compartments to compress and cause at least one adjacent one of the plural compartments to expand substantially simultaneously.
 9. The micro-pump of claim 1 further comprising a drive circuit to produce waveforms to apply to the electrodes.
 10. A micro-pump comprising: first and second micro-pump modules having a pump body, a membrane having electrically conductive electrodes on major surfaces thereof, and a pump end that form a pump compartment, each of the first and second micro-pump modules having at least an inlet port providing fluid ingress into the pump compartment and an outlet port providing fluid egress from the pump compartment; at least a third micro-pump module having a pump body and a membrane having electrically conductive electrodes on major surfaces thereof, with the third micro-pump module sandwiched between the first and second micro-pump modules.
 11. The micro-pump of claim 10 wherein the inlet and the outlet of each module are on a same wall of the pump body, and the micro pump comprises electronic drive circuitry.
 12. The micro-pump of claim 10 wherein the first plurality of inlets and the second plurality of outlets are on the same wall of the pump body, and the first plurality of inlets have a first set of connections to a source and the second plurality of outlets have a second, different set of connections to a sink and with the second plurality of outlets isolated from the first set of connections.
 13. The micro-pump of claim 10 wherein the inlet and the outlet of each module are on opposing walls of the pump body.
 14. The micro-pump of claim 10 further comprising a plurality of valves disposed adjacent inlets and outlets.
 15. The micro-pump of claim 10 wherein the valves are flap valves having a beam member and a stop.
 16. A cooling device for an electrical component, the cooling device comprising: a micro-pump having a pump body forming a pump chamber having a plurality of compartments, with the pump chamber having a first plurality of inlet ports providing fluid ingress into compartments of the pump chamber and a second plurality of outlet ports providing fluid egress from compartments of the pump chamber and a third plurality of membranes disposed in the pump chamber, with the third plurality of membranes anchored between opposing walls of the pump body, and a fourth plurality of electrodes, with a first pair of the fourth plurality of electrodes disposed on a second different pair of opposing walls of the pump body, and a remaining portion of the fourth plurality of electrodes disposed on a surface of each of the membranes; a heat plate having a first surface configured to attach to the electrical component and a second surface that is in thermal communication with the micro-pump.
 17. The cooling device of claim 16 wherein the micro-pump is connected to the heat plate.
 18. The cooling device of claim 16 wherein end ones of the compartments have a corresponding wall of the pump body and one of the third plurality of membranes providing the end compartments and with intermediate ones of the compartments having a pair of membranes providing the intermediate compartments.
 19. An airway pressure breathing device comprises: a body having air passages through the body terminating in a pair of end portions, with each end portion having at least one outlet in a first surface of the end portion; and a micro pump supported by the body, the micro pump configured to pump ambient air through the air passages in the body to the end portions.
 20. The airway pressure breathing device of claim 19 further comprising: a battery to provide a power source for the micro pump, the battery supported on the body.
 21. The airway pressure breathing device of claim 19, further comprising: a butterfly type valve disposed in fluid communication with the micro pump.
 22. The airway pressure breathing device of claim 19, further comprising: a pair of plugs having air passages at the end portions of the body.
 23. The airway pressure breathing device of claim 19, wherein the end portions comprise a nasal interface that snugly fits within nostrils of a user.
 24. The airway pressure breathing device of claim 19, further comprising: a nasal interface at the end portions, which nasal interface configured to snugly fit within nostrils of a user.
 25. A valve device comprising: a body having a passage, the body supporting: an inlet control port perpendicular to the passage; a first port coupled to the body at a first end of the passage; a second port coupled at a second end of the passage; an axial member; and a valve flap disposed in the body adjacent the inlet control port, the flap valve being rotatable about the axial member to open and close the passage between the first and second port upon application of air through the inlet control port.
 26. The valve device of claim 25 wherein the first port supported on the body is offset slightly from a center of the valve flap.
 27. The valve device of claim 25 wherein the flap provides a butterfly type valve disposed in fluid communication with the inlet control port that is controlled by air applied to the inlet control port.
 28. The valve device of claim 25 further comprising a third port, the third port disposed at the first end of the passage, adjacent to the first port supported, the third port supported on the body.
 29. The valve device of claim 25 further comprising a third port, the third port disposed at the first end of the passage, adjacent to the first port supported, the third port supported on the body and being offset slightly from a center of the valve flap.
 30. A valve device comprising: a valve member, the valve member having a stem portion and flap cover portion with the stem being perpendicular to the flap cover portion; a body layer; a body wall supported on the body layer, the body wall having a passage, the passage in body wall having an opening into a chamber formed from the body layer and body wall and at least one opening beyond the body wall, formed by a pair of spaced body wall regions with the stem portion within a space defined by the pair of spaced wall regions, and with flap cover portion within the passage between the opening in the chamber and the opening beyond the wall.
 31. The valve device of claim 30 further comprising a second body layer disposed over the body wall.
 32. A valve device comprising: a body layer; a valve member, the valve member having a somewhat semi-circular portion, a pair of end-portions coupled to ends of the semi-circular portion and a pair of leg portions; a piston-like member having a stem portion and a head portion, the piston-like member supported on the body layer; a body wall supported on the body layer, the body wall having an opening into a chamber formed from the body layer and the body wall and at least one opening beyond the body wall formed by the stem portion of the piston-like member, with the head portion configured to allow the valve member to freely move but be contained adjacent to the opening beyond the wall.
 33. The valve device of claim 32 further comprising a second body layer disposed over the body wall.
 34. The valve device of claim 32 wherein the shape of the valve member roughly resembles the Greek letter omega. 